Subsoil plow point

ABSTRACT

An improved plow point such as used on a chisel plow has a forward tooth for breaking the soil. Wings extend outwardly and rearwardly of the tooth portion of the tool at a shallow angle. That is, the leading edges of the wings slope downwardly and slightly rearwardly from the tooth. After the tooth breaks the soil, the wings raise, twist and turn the broken deep soil. This lifting action provides aeration of the soil. The wings also bring up some deep soil and leave large chunks of soil that become mellow due to the freezing and thawing cycles during the winter. The outboard rear edge of each wing may be turned slightly downward which enhances the twisting motion of the soil. All of this is done without creating a plow sole.

RELATED APPLICATION

This is a division of application Ser. No. 531,169, filed Sept. 9, 1983which is a division of application Ser. No. 220,419, filed Dec. 29,1980, now abandoned which in turn is a continuation in-part of myco-pending application for ONE PASS COMPLETE TILLAGE SYSTEM, filed Aug.17, 1978, Ser. No. 934,585 now U.S. Pat. No. 4,245,706.

BACKGROUND OF THE INVENTION

The present invention relates to an agricultural tillage system whichincludes a novel plow point tillage system which is capable of acomplete working and plowing of unplowed ground in a single pass.

Perhaps the most commonly used tool for plowing is the conventionalmoldboard plow. Usually the plow bottom is set at a particular depth ofplowing, for example, eight or ten inches, but as deep as twelve orfourteen inches in some cases. These plows are typically mounted to amain beam which is inclined relative to the direction of travel of atractor so that each moldboard is set to take a swath or strip ofground, cut it, and roll the ground over into a furrow formed by thenext forward moldboard. The leading moldboard turns its strip of groundover into a furrow formed on a previous pass of the plow system.

When a moldboard plow is used repeatedly to plow ground at the samedepth, a layer of highly compacted soil is formed just beneath thatdepth. This is called the plow "sole", and it has the disadvantagesthat, due to its compactness, roots of plants have difficulty inpenetrating it, and water has a tendency to drain over the plow solerather than being absorbed by the soil. Further, a moldboard plowdisplaces to one side all of the soil that is tilled. Eventually, theground must be plowed in the opposite direction, and even when thisoccurs, a deep side ridge normally is left at the end swath.

One advantage of the moldboard plow, not found in devices which work amore shallow depth is that they bring up deep soil and this is believedto be effective in reducing herbicide built up near the surface.

A commonly used plow point is made from a bar of steel approximatelyfour inches wide that is curved to bolt in front of a chisel plow shank.It is twisted on a helix and right and left hand units are used. Due tothe wide curved surface, the point tends to bulldoze the soil and powerrequirements become high at deeper depths. Another common point is anapproximate two inch wide point mounted to a thick plate shank. Theseunits are generally operated at deeper depths, however, in wetconditions, they tend to simply cut a path.

SUMMARY OF THE INVENTION

The present invention is directed to a plow point for a tillage systemwhich is designed to do complete tillage of the soil in a single pass.That is, it cuts and buries trash, and it also provides a controlledamount of deep soil plowing without creating a plow sole. Thesefunctions are achieved through the cooperative action of widely spaceddisc blades at a forward position.

Located behind the blades are novel tools or plow points which arelocated in the strips of soil left untilled by the blades with mixedtrash and soil accumulated on top of these strips from the action of theblades. These tools each include a forward tooth for breaking the soilbeneath the level of working of the disc blades. Wings extend outwardlyand rearwardly of the tooth portion of the tool at a shallow angle. Thatis, the forward edges of the wings slope downwardly and slightlyrearwardly from the point at which they join with the tooth. After thetooth breaks the soil, the wings raise, twist and turn the broken deepsoil, thereby mixing the trash with top soil, evenly distributing themixed soil and trash over the ground, burying a controlled amount oftrash, and bringing up some deep soil. The outboard rear edge of eachwing may be turned slightly downward which enhances the twisting motionof the soil. All of this is done without creating a plow sole. Thebroken deep soil is better able to absorb water and become worked by thewinter's freezing and thawing cycles.

The structure which cooperates to avoid creation of a plow sole includesthe cutting edge of the tooth which is relatively narrow; the shape andorientation of the wings, the function of which is to lift, twist androll the soil, without creating lateral displacement of the soil to anysubstantial extent; and the slope and location of the leading edge ofthe wings in relation to the shape and position of the tooth, whichprovides clearance for soil to pass beneath them without compacting it.

In summary, the present invention provides complete tillage in one-passsystem wherein forward, widely spaced disc blades are used to break upand windrow trash and soil while leaving untilled strips of substantialwidth, and rear plow points break the soil beneath previouslyundisturbed strips on which some mixed trash and top soil preferablyhave been accumulated. The points twist and roll the broken soil,thereby mixing the trash with top soil, laterally distribute the mixedsoil and trash, bury a controlled amount of trash, and bring up somedeep soil. This is all accomplished without creating a new plow sole ordigging up the buried trash, and while leaving the tilled soil free ofridges and furrows so that it can be subsequently seeded withoutsubstantial additional tillage. Further, the apparatus does not cause anet lateral displacement of soil, so that it can work the soil in eitherdirection relative to a previously worked swath.

Other features and advantages of the present invention will be apparentto persons skilled in the art from the following detailed description ofpreferred embodiments, accompanied by the attached drawing whereinidentical reference numerals will refer to like parts in the variousviews.

THE DRAWING

FIG. 1 is a plan view of an apparatus incorporating one embodiment ofthe present invention attached to the rear of a tractor, which is shownin fragmentary form;

FIG. 2 is a right side view of the apparatus of FIG. 1 in use, with thetractor again shown in fragmentary form;

FIG. 3 is a vertical illustration of the soil being worked from behindthe plow points which are shown in fragmentary form, and illustratingthe operation of the present invention; and

FIGS. 4 and 5 are frontal perspective and front elevation viewsrespectively of an improved plow point for the system of FIG. 1.

FIG. 6 is a plan view of the improved plow point for the system of FIG.1;

FIG. 7 is a lower rear perspective view of the plow point of FIG. 4illustrating its attachment to a shank, with the parts shown in explodedrelation;

FIG. 8 is a perspective view of the plow point of FIG. 4 illustratingits operation in the soil;

FIG. 9 is a diagrammatic plan view of a portion of the system of FIG. 1illustrating its operation;

FIG. 10 is a soil profile illustrating the operation of the apparatus ofFIG. 9;

FIG. 11 is a close up side view, partly in cross section, showing themounting of a disc blade;

FIG. 12 is a plan view of an alternate tillage system incorporating theinvention;

FIG. 13 is a side view of the embodiment shown in FIG. 12;

FIG. 14 is a frontal, side perspective view of an alternative plowpoint;

FIGS. 15 and 16 are respectively side and front views of the plow pointof FIG. 11;

FIG. 17 is a diagrammatic plan view of a portion of the system of FIG.12 illustrating its operation; and

FIG. 18 is a soil profile illustrating the operation of the apparatus ofFIG. 17.

DETAILED DESCRIPTION Embodiment of FIGS. 1-11

Referring first to FIG. 1, reference numeral 10 generally designates theoverall machine which is shown as being pulled toward the top of thepage by a traction vehicle designated T. The plow system includes arigid frame generally designated 11 attached to the rear of the tractorby means of a hitch point 12.

The main frame 11 includes first and second elongated side frame members14, 15 which are braced by a first cross frame member 16 and also by amain cross member 17 which is connected to support wheels 19, 20 as willbe described. A forward box-shaped frame generally designated 23includes forward and rear transverse frame members 24, 25 welded to thetop of the inclined side members 14, 15. The outboard ends of thetransverse frame members 23, 24 are braced by longitudinal side framemembers 27, 28 respectively.

A first or forward set of disc blades (sometimes referred to simply as"discs" or "blades") generally designated 30 is mounted to the forwardcross frame member 24; and a second or rear set of similar disc blades32 is mounted in a similar fashion to the rear transverse frame member25 of the box frame member 23. The mounting structure for the discblades will be described presently. The individual blades of the forwardset are designated 30A-30J respectively and the individual blades of therear set are correspondingly designated 32A-32J respectively.

Each of the disc blades is mounted for rotation about a horizontal axis,such as that designated 33 for the disc 30C which defines an angle, W,called the working angle relative to a line transverse of the directionof travel. For the present invention, the working angle isadvantageously within the range 24°-34° and preferably about 30°. Thespacing of adjacent disc blades and the relative placement ofcooperating front and rear disc blades will be described below.

Turning now to the rear of the frame 11, a plow point support framehaving the general shape of an inverted V and generally designated byreference numeral 35, includes first and second side members 36, 37which are braced by an angle iron 38, and are attached to the transverseframe member 17 by horizontally extending connection members 40, 41.

A set of plow points generally designated 43 and including nineindividual points designated respectively 43A-43I are mounted to thepoint support frame 37, as best illustrated in FIG. 2.

The support wheels 19, 20 have their axles journaled respectively inarms 48, 49 which, in turn, are pivotally connected at 50 and 51 tobrackets 52, 53 respectively, which are welded to the outboard ends ofthe transverse frame member 17.

A rock shaft 55 is supported in pillow blocks 56, 57 mounted to theinclined side frame members 14, 15; and its outboard ends, whichterminate respectively above the wheel support arms 48, 49 there arewelded first and second links 60, 61, the lower ends of which are pinnedto the wheel support arms 48, 49 (see the right side link 61 in FIG. 2.)The upper portions of these links are connected to second links, one ofwhich is shown at 63 in FIG. 2 which are, in turn, secured to the rockshaft 55.

Still referring to FIG. 2, a link 65 is rigidly connected to the centerof the rock shaft 55, and its upper end is pivotally connected to therod end of a hydraulic cylinder and rod unit generally designated 66,the cylinder end of which is pinned at 67 to the cross frame member 16of the main frame. When the hydraulic cylinder unit 66 is extended (thecontrols are preferably located adjacent the driver's location on thetractor T), it cranks the arm 65 to rotate the rock shaftcounterclockwise in FIG. 2, thereby urging the wheel support arms 48, 49downwardly, and raising the main frame 11 and the plow point frame 35 inunison. In this manner, the working depth of the plow points isadjusted. The cylinder 66 is a double-acting cylinder which is connectedto the operator's control in a conventional manner by two hydraulichoses which are omitted for clarity.

Turning back to FIG. 1, it will be observed that for the forward set ofdiscs 30, those to the left of the center line of the machine have theirworking surfaces facing toward the left of the machine to displace soiland trash in that direction. Similarly, those to the right of the centerline of the machine in the forward set 30 face to the right. Adjacenteach of the outboard discs 30A and 30J, there are located dirt shieldsdesignated respectively 70 and 71, see the shield designated 71 in FIG.2. Each is mounted in a similar fashion.

Turning then to the shield 71, it includes two sets of vertically spacedapertures generally designated 73, 74 for mounting to upright angleirons 75, 76 respectively by means of a pair of forward bolts 78 and apair of rear bolts 79. Additional holes are provided at the same spacingin the dirt shild so that it may be adjusted up or down, as desired.Further, the lower portion of the leading edge of the dirt shield iscurved as at 80 so as to prevent the accumulation of trash or weedsduring operation.

The discs 32 on the rear set have their working surfaces facing towardsthe center of the apparatus and consequently displaces soil inwardlythereby obviating any build up of soil or a net displacement of soiloutside the swath cut by the apparatus. This permits the apparatus towork the soil in either direction relative to a previously worked swath.The outermost blades 22 on the rear set, if they are the same size asthe other blades, can be mounted one inch higher and at a slightlylesser working angle, preferably slightly less than 25°, so as to avoidleaving a furrow. Alternatively, raker blades of smaller diameter can beused since the only function of these blades is to fill the furrow leftby the associated blade in the forward set.

Thus, all the blades in both the front and rear sets face in the samedirection for each quadrant of the machine. This avoids a tendencytowards clogging or plugging as might occur with adjacent blades facingeach other.

Turning now to the mounting of the blades, each of the blades is mountedon an upright support, such as that designated 85 for the blade 30J,which support is welded to the rear surface of the crossbar 24. Arearwardly extending bracket (FIG. 1) is pivotally mounted at 87 of FIG.2. A spring 90 urges the bracket 86 downwardly by reaction against theupright support member 85 to cause the discs to engage the soil forpenetration while permitting them individually to ride over rocks orstumps.

The blade 30J is mounted to a spindle 82A which is journaled in a hub82B. The hub 82B is welded to a plate 82C which, in turn, is bolted tothe bracket 86 by means of a forward and a rear bolt, the rear boltbeing seen in FIG. 11 and designated 82D. The forward bolt acts as apivot point, and the rear bolt is received in a laterally elongated slot82E formed in the bracket 86. By means of this arrangement, the bladescan be individually adjusted by rotation about vertical axes. Byrotating the disc to cut a wider path (i.e. increasing its workingangle), more soil will be displaced laterally, and during operation, thesoil and trash will be thrown more to the side than for a smallerworking angle.

The sets of blades, when thus arranged, leave strips or swaths which arealternately cleared and undisturbed, at least some of the cleared trashbeing accumulated onto the strip of undisturbed soil. It will beobserved from FIG. 1 that the blades of both sets are spaced to leavestrips of soil of substantial width in relation to the width of acleared swath, preferably, the spacing of adjacent blades facing thesame direction is at least 80% of the width of a swath cleared by ablade. The outermost blades in the second line, 32A, 32I may be spacedlaterally inwardly at a slightly narrower spacing than normal since theyare normally angled less. On the large rear chevron frame comprisingbeams 35, 36, there are nine individual plow points designatedrespectively 43A-43I, at equal lateral spacings.

Turning now to FIGS. 2 and 4-7, each of the plow points is similar instructure, and each is mounted on a heavy shank 73, which isconventionally mounted to one of the beams 35, 36. The lower end of theshank forms a nose, the upper surface of which is designated 75, andthis forms a bearing surface for a groundbreaking and working tool orpoint generally designated by reference numeral 99. A transverseaperture 81 is formed in the nose of the shank 73 for securing the tool99 by means of a bolt 83 and nut 83A.

The tool 99 is seen to comprise a narrow, flat member 91 (sometimescalled a "tooth") which may be formed from hardened bar stock, andhaving a lower, sharpened cutting edge 92. First and second mountingplates 93, 93A are welded to the bottom surface of the tooth 91, andthey are held apart by a spacer 93B. Slots 94, 94A are formed in themounting plates 93, 93A for alignment with the aperture 81 on the noseof the plow shank, for receiving the bolt 83.

A pair of wings 95, 96 are welded to the sides of the tooth 91, and theyare braced against the tooth and the mounting plates by triangular bracemembers 97A, 97B respectively. As best seen in FIGS. 4 and 5, when thepoint is in the working position, the leading edges 95A, 95B of thewings 95, 96 are sloped downwardly and rearwardly. The rearward slope ofthe leading edges 95A, 96A relative to a line transverse of thedirection of travel of the plow tip (designated 99A in FIG. 6) ispreferably about 30° for most soil conditions found in the Midwest ofthe United States. For general conditions, this slope is less than orequal to 30°, in the range of 25°-32°, although, if soil ridging isdesired for snow or water retention, the slope may be up to 40°.

The inboard ends of the leading edges 95A, 96A are designatedrespectively 95B and 96B in FIG. 5, and the location at which thesepoints join the tooth 91 are above the leading cutting edge 92. Theupper, working surfaces of the wings 95, 96 may be slightly concave; andtheir outboard rearward edges 95C, 96C may be formed downwardly out ofplanar relation with the rest of the upper surface of the wing to reducelateral throwing of soil. The formation of the wing in which theoutboard rear end is turned downwardly so that the wing appears bentalong a diagonal parallel to the lines of shading in FIG. 4, has thefurther effect that the soil adjacent the inboard edges of the wings istwisted more than the soil lifted by the outboard edges. As shown inidealized form in FIG. 8, the twisting motion causes the soil to turnabout an axis parallel to the direction of travel of the vehicle asindicated by the large arrows. It will be appreciated that trash and topsoil has been windrowed above the strip of ground worked by the plowtip, and the windrowed soil and trash is also caught up in the twistingmotion caused by the plow tip and buried.

In summary, the curvature of the working surfaces of the wings, togetherwith the rearward and downward slope of the leading edges of the wings,the relationship of the placement of the wings to the leading edge ofthe tooth, and the downwardly turned outboard rear edges of the wingscooperate to induce a twisting, turning motion to soil loosened by thebreaking action of the tooth without displacing that soil laterally toany substantial degree. In other words, most of the trash remains in thesame general swath worked by the point; although some will obviously bethrown sideways depending on the soil and operating speed. By impartinga twisting, turning motion to the soil, the previously undisturbed soilabove the wings is turned over to cover the trash accumulated on thepreviously untilled strip and to bury the trash in the furrow cut by theplow tip. Further, due to the depth at which the plow tip works, and thesoil profile formed by the preceding blades, the sub-surface soil isfractured and broken but not vertically displaced substantially abovelines such as the dashed lines illustrated in FIG. 3 and designated 98.This has the advantage of breaking up soil beneath the surface toincrease its ability to absorb moisture while reducing erosion becausethe trash is mixed throughout the upper surface to hold down the surfacesoil. With a high moisture content, the large pieces of soil beneath thesurface will, upon the repeated freezing and thawing of winter, create amore mellow subsoil. It will also be observed that the blades work atone depth and in one swath; the wings work a deeper depth and differentswaths; and the teeth work a still deeper depth and narrower, differentswath. This reduces any tendency to create a plow sole or "hard pan" asthe soil is tilled year after year.

Operation of Embodiment of FIGS. 1-11

Returning now to FIG. 1, the centers of the blades of the forward set 30are laterally spaced at a distance which is greater than the diameter ofthe blade. In other words, the lateral distance between correspondingparts of adjacent blades facing the same direction is greater than thediameter of the blades. For example, if 24 inch or 26 inch blades areused, then the blades are set at a spacing of approximately 30 inches oncenter. This is not so for the adjacent center blades 30E and 30Fbecause they throw the cleared top soil in opposite directions.

The blades on the second set 32 are also widely spaced in the samemanner; they are located relative to an associated blade on the firstset such that the blade on the rear set parts the windrow of mixed soiland trash formed by the associated blade on the first set. A pair ofblades, one of the first set and one of the second set, are said to be"associated" with each other or in "cooperating" relation with eachother when the blade on the rear set works not only the previouslyundisturbed soil, but also some of the mixed soil and trash that hadbeen windrowed onto that strip by the "associated" forward blade. Forexample, referring now to FIG. 9, the blade 30I of the forward setclears a path 102, and the trash and top soil cleared from that path aredisplaced to the right onto a windrow at 104. The leading edge of theblade 32I on the rear set is such as to part the windrow 104 and toclear a second strip of ground 105, see also FIG. 10.

The trailing edges of the forward blade 30I and the rear blade 32Ioverlap slightly so as to insure that both blades cooperate to form asingle wide furrow such as is shown in the soil profile of FIG. 10 at102A, 104A. It will be appreciated that the actual width of a stripworked by a blade is less than its diameter since the axis of the bladeis located above the soil and it is turned at a working angle. Theleading edge of a blade has a tendency to cut a clean furrow wall, butthe trailing edge, due to lateral forces created by the blade on thesoil, has a tendency to scoop out soil laterally. Further, where thestrip adjacent a rear blade is already cleared and the soil is weakenedalong a furrow wall, the action of a rear blade will be to break awaythe top of the wall. For example, the furrow cut by the disc 30B isdesignated 108 in the close up view of FIG. 3. It may have a depth offour to six inches and a width of ten to twelve inches for a bladehaving a diameter of twenty-four inches and a working angle of 27°. Itdisplaces the soil it tills to the left. The blade 32B clears anadjacent strip and displaces that soil toward the right. It forms afurrow such as that shown at 109. However, because of the lateral forcecreated by the trailing edge of the blade 32B, and because it is workinginto the already-formed furrow 108, it breaks away the soil to a depthsuch as indicated at 110. The plow point 43A works the strip ofpreviously untilled soil represented by 112 and on which a windrow hasbeen formed by the cooperative action of blades 30A, 30B and 32A. Itwill be appreciated that the blade 30A directs its soil to the leftagainst the dirt skirt 70 to form a windrow which is then thrown to theright by blade 32A.

In the first embodiment, the shank of the plow point 43A is preferablylocated off-center relative to the strip 112. In other words, the shank43A is offset laterally relative to the center line of the strip ofuntilled soil on which trash is windrowed. The working depth of a plowpoint is deeper than that of a furrow cut by a blade. In this example,the plow point may be working at a soil depth of ten to twelve inches.By placing the shank of a plow tip off center relative to the strip ofpreviously untilled soil in which it works, any trash that wouldotherwise have a tendency to bridge across the plow shank will flow tothe side because of unequal drag forces causing it to slide off theshank as the shank passes. Thus, there is no accumulation of trash onthe shank. This is important because any accumulation of trash will notonly greatly increase the drag on the apparatus, but it will have atendency to cause the trash to be discharged in large clumps on thesurface after build up, and thereby defeat a primary purpose of theapparatus which is to achieve a controlled burying of the trash.

In this example, the shanks of the plow points are on thirty inchcenters, and the nominal width of an untilled strip such as 112 in FIG.3 may be about six to seven inches. The center of the shank of the plowtip 43A is located approximately two to two and one-half inches from thewall of the furrow 109, and five to five and one-half inches from thewall of the furrow designated 115 which is formed by the blade 32A.

Because of the formation of the furrows by the plow blades, the top soilwill be weakened and partly broken, and in addition to the soil abovethe plow points which is twisted as described above to bury the trashwindrowed above the strip of soil 112, the soil between the plow pointsbeneath the blade furrows is broken into large pieces, but notdisplaced, as diagrammatically represented by the fracture line 98 inFIG. 3. All of the furrow walls and lines indicated above for purposesof explanation are, of course, idealized in the sense that they will notoccur as straight lines or smoothly curved lines in the field, and therewill be variation for different soil conditions. The soil profile isdisclosed merely for purposes of explaining the major functionsperformed by, and the interrelationships of, the elements of theapparatus.

As mentioned, when the strip 112 is tilled by the plow point, the soilis twisted by the action of the plow point, as diagrammaticallyillustrated by the arrows in FIG. 3, and the showing of FIG. 8; and somedeep soil is brought up and mixed with the trash that has been windrowedon top of the strip, as well as the trash not yet worked on the strip112. It is desirable to have some trash at the top of the soil to reducesurface erosion by wind and water. However, most of the trash is buriedand mixed with the soil to promote decay.

It will also be appreciated that the blades work the soil at one depth(e.g. 5 in.); the wings at another, greater depth (6-7 in.); and thepoint at a still greater depth (10 in.). This reduces any tendency toform a plow sole or "hard pan" as it is sometimes called.

Referring again to FIG. 8, the action of the plow point as it is pulledthrough the ground is, as mentioned, diagrammatically illustrated. Thecutting edge 92 on the tooth 91 has the effect of breaking the groundimmediately preceding it. The upward, rearward inclination of the tooth91 (namely, on the surface designated 91A in FIG. 8) assists in liftingthe soil and causing further breaking of that soil. The wings, on theother hand, take the broken soil and displace it in the direction of thelarger arrows 105, causing it to twist in the shape of a vortexdownwardly in a smooth conformation. This action is promoted by the factthat the leading edges of the wings extend downwardly and outwardly aswell as slightly rearwardly from their intersection with the tooth 91.The twisting, turning soil further breaks apart, some of which, aftermixing with accumulated trash, fills the void left by the tooth, and theremainder spreads evenly over adjacent areas due to the impact of theplow points. The clearance beneath the wings avoids compacting the soilwhile permitting this action.

Because of the cooperative action between the disc blades in removingstrips of top soil as indicated above, as well as the structure andoperation of the plow points at the high speeds at which this machine isdesigned to operate, the final soil profile is made relatively free ofdeep ridges and furrows. By placing the shanks of the plow points closerto one furrow wall than the other in the untilled strips, there is lessof a tendency for trash to bridge across and accumulate on the shank.

Referring back to FIG. 1, it will also be appreciated that the supportwheels 19, 20 do not leave compacted strips of soil because they arelocated to ride in strips of untilled soil left respectively betweenblades 30C and 32D, and blades 30H and 32G. Plow points 43C and 43G workthe soil in these strips after the support wheels have passed, and theapparatus has the advantage that the support wheels do not run infurrows, thereby permitting the apparatus to ride evenly and with morestability.

Embodiment of FIGS. 12-18

Turning now to FIGS. 12 and 13, a draft frame is generally designated byreference number 115, again having a general chevron shape. A forwarddisc blade frame is generally designated 116, and it is verticallyadjustable relative to the draft frame by means of a parallel liftmechanism generally designated 117. A plow point frame generallydesignated 118 is mounted to the rear portion of the main draft frame115. A pair of support wheels 119, 120 are mounted to the rear frame 118by means of a height adjustable mechanism generally designated 125 andactuated by means of a hydraulic cylinder 126, similar to that which hasalready been described in connection with the first embodiment.

As best seen in FIG. 13, the forward frame 116 is raised by retractionof an adjusting mechanism including an hydraulic cylinder 127. Theadjustment mechanism also includes an actuator arm 128 pivotallyconnected to the rod end of the hydraulic cylinder 127. The other end ofthe actuator 128 is attached to a shaft 134 (FIG. 12) which is rotatablymounted to the main frame 115. A link 129 is welded at one end to rotatewith the shaft 134 and has its other end pivotally connected to theframe 116. A parallel linkage generally designated 130 is alsocontrolled by actuator 128 and shaft 134, and it extends rearwardly tooperate a crank 131 mounted to a rear shaft 134A and connected to liftthe rear of the disc blade frame 116. A similar parallel linkage islocated on the other side of the frame (see FIG. 12) for stability inlifting the frame. The two parallel linkages are connected together bymeans of the crank shafts 134, 135 which are, in turn, secured to thedraft frame 115 to act as a base against which the forward or disc bladeframe 116 is raised. The link 130 may be a turnbuckle link, as shown, tomake minor adjustments in the operating depths of the front and rearsets of disc blades.

Although the actuating mechanisms for the rear crank shaft 134A havebeen described as "parallel" linkages, the long horizontal links can bemade adjustable in length, or, as is preferred, the rear shaft 134A canbe mounted slightly lower than for a true parallelogram linkage. Thiswill accommodate the tolerances and wear involved to maintain the frontand rear sets of blades at equal and uniform depths under useconditions.

Referring now to the rear frame 118, a first plurality of plow pointsdesignated 140A-140F are secured in a first transverse line, and asecond plurality 141A-141E are secured to the rear frame 118 along asecond line.

Turning now to FIG. 13, the plow points are each similarly mounted,including a curved spring shank 145 which is mounted by a conventionalspring mount 146 to the frame 118. Each spring shank is provided with aground working tool or plow point generally designated 150 and seen inmore detail in FIGS. 14-16.

The plow point 150 includes a downwardly and forwardly curved tooth 151which is narrowed to a point at 152 and has a central work surface 153generally in the shape of a knuckle. Immediately behind the work surface153, the tooth slopes at 154 to conform to the narrow width of the shankportion of the tooth.

As with the previous plow point, a pair of wings 160, 161 extendlaterally of the tooth 151, and they are provided with associatedleading edges 160A and 161A which are sloped rearwardly and downwardlyfrom locations 160B and 161B to the rear of and above the point 152. Thework surfaces 160C, 161C are also concave to provide the rolling,twisting action for the broken soil. The shape of the leading edges andtheir relationship to the work surfaces 153 and point 152 againeliminate the creation of a plow sole even for repeated passes. Theembodiment of the plow point and spring shank of FIGS. 12-16 is designedfor more shallow working of the soil than is the case with the firstembodiment.

In this embodiment, the size and working angles of the disc blades aresimilar to that disclosed in connection with the first embodiment,however, the disc blades are located at a wider setting. That is, thedisc blades are set on forty inch centers. Further, the blades on therear set are centered on the spaces between the blades on the forwardset of blades.

This arrangement leaves strips of untilled soil between the workingsurfaces of the blades as well as the non-working surfaces. One set ofplow points (the forward set in the illustrated embodiment, althoughthat is not necessary) is located on twenty inch centers in the stripsof untilled soil between the working surfaces of associated blades fromthe front and rear sets; and the other set of plow points (also ontwenty inch centers) is located in the strips of untilled soil betweenthe non-working surfaces of the blades which face or oppose each other.

Because there are more plow points in the second embodiment, the pointsillustrated in FIGS. 14-16, which are narrower than those of the firstembodiment may be used. The nominal width of the untilled strips isapproximately the same, however, for both embodiments.

Operation of the Embodiment of FIGS. 12-18

Referring back to FIG. 12, as indicated, there are two sets of discblades, forward and rear. The apparatus to the right of the center lineextending in the direction of travel operates similar to that located tothe left of the center line, so only one side need be explained for afull understanding. In the forward set, the three blades to the left ofthe center line, 135A-135C, each till a strip and throw soil in the samedirection (namely, to the left). The blades are all widely spacedrelative to each other. The three associated disc blades 137A-137C inthe rear set face the other side. The blades of the rear set are locatedso as to part the windrow created by the associated blade in the forwardset, partially filling the furrow left by the associated blade of theforward set and also creating a second windrow of soil and trashdisplaced in the opposite lateral direction. The windrows are created onboth strips left untilled.

Referring now to FIGS. 17 and 18 which show the right side of theapparatus of the second embodiment, blade 135E of the forward set clearsa strip and forms a first furrow designated 160. The soil and trashtilled by the blade 135E are mixed, forced laterally to the right, andspread across a path in front of blade 137E as well as on both sides ofthat blade. That is, blade 135E of the first set windrows the soil andtrash it tills onto a strip which extends from its trailing edge over tothe line 161 representing the path of the leading edge of blade 135F.The windrow is not of uniform depth, and obviously the path on which itis thrown is not so well defined--some of the soil and trash mixture isthrown so far as to enter the furrow formed by the blade 135F.

The blade "associated" with blade 135E is the blade 137E; and that bladeparts the windrow formed by blade 135E and clears its own strip 162. Thewindrowed soil taken by blade 137E and the previously undisturbed soilit tills from the furrow 162 are also thrown over a wide path to theleft of blade 137E. Some of this soil partially fills furrow 160; someis displaced even to the left of furrow 160; and some is thrown onto astrip 165. The strip 165 is located between the working surfaces of theassociated pair of blades 135E, 137E; and soil from both blades willhave accumulated on it, though not a substantial amount. Strip 165 liesin the path of plow point 140E which then does some deep tilling andforces the windrowed soil laterally into furrows 160 and 162 to even thecontour.

To the right of blade 137E is a strip 166 on which at least some soilwill have been windrowed from blade 135E of the forward set and blade137F of the rear set. Strip 166 is located between the non-workingsurfaces of blade 135F and 137E; and it lies in the path of plow point141F. Point 141F performs deep tillage of the soil beneath that stripand forces the windrowed soil mixture to be buried as well as to atleast partially fill furrow 162 and a furrow 167 behind blade 135F.

Thus, the combination of first and second lines of disc blades formsalternate strips of (a) cleared ground or furrow; (b) first windrows(previously undisturbed ground on which some accumulated debris has beenthrown, the amount depending on the angle of the blades, the speed ofthe vehicle, etc.); (c) furrow at least partially filled with a loosemixture of trash and top soil; and (d) second windrows. The firstwindrows are formed between the working surfaces of an associated pairof blades, one from the forward set and one from the rear set. Thesecond windrows are formed between the non-working surfaces of one bladefrom the forward set and one from the rear set.

As with the previous embodiment, the support wheels 119, 120 are locatedto ride in strips of untilled soil left respectively between blades 135Aand 137B, and blades 137E and 135F. Plow points 141A and 141E work thesoil in these strips after the support wheels have passed, but theapparatus has the advantage that the support wheels do not run infurrows, thereby permitting the apparatus to ride evenly and withgreater stability, and they do not leave strips of compacted soil.

Both embodiments provide a first working of the top soil with the discblades which cut the trash and windrow at least a portion of it. Thelateral spacing of the blades is made wide so as to leave swaths ofundisturbed soil of substantial width in relation to the width of thecleared swaths. Hence, the blades also windrow or accumulate mixed trashand top soil. A second line of blades located in previously undisturbedsoil, parts, windrows and moves the first windrow in the oppositedirection. The blades are followed by a plurality of plow pointsincluding tools which are located in the strips of previouslyundisturbed soil on which trash and top soil have been accumulated bythe blades.

The plow points not only break the soil at a location deeper than wasworked by the blades, but they are provided with wings which twist andturn the soil, replacing the soil dug out with trash and top soil andcausing an even distribution of the mixed soil and trash across theentire width of the system. The plow points bring up deep soil withoutcreating a plow sole. In the case of the embodiment of FIG. 12, theblades are mounted on a vertically adjustable frame so as to control theworking depth of the blades. The deeper the blades work, the deeper willthe trash ultimately be buried, as may be useful in slightly sloped orflat terrain. If the blades work at a more shallow depth, more trashwill be at the surface, and this may be useful in controlling erosion.By placing the cutting edge of the point beneath the level at which theblades work, and by accumulating mixed trash and soil on the top ofpreviously undisturbed ground, the plow points do not dig up buriedtrash--rather, they bury trash accumulated on top of the area beingworked. This is accomplished principally through the twisting, turningaction provided by the rearwardly and downwardly swept wings.

By placing the disc blades at a wide spacing as defined above and byarranging subsequent lines of blades to split windrows created byprevious lines, while forming their own windrows, the number of bladesis reduced relative to conventional ganged disc blades, therebyincreasing the weight and drawbar pull per blade for a given design andhorsepower; and the spacing of plow points can be much wider than isfound in conventional chisel plows.

Having thus disclosed preferred embodiments of the invention, personsskilled in the art will be able to modify certain of the structure whichhas been disclosed and to substitute equivalent elements for thosedescribed while continuing to practice the principle of the invention;and it is, therefore, intended that all such modifications andsubstitutions be covered as they are embraced within the spirit andscope of the appended claims.

I claim:
 1. A plow point for soil tillage adapted to be mounted on ashank comprising: an elongated, narrow tooth extending forwardly anddownwardly of said shank and defining a horizontal cutting edgetransverse of the direction of travel for breaking soil and an upper andrearwardly inclined work surface for lifting the broken soil; and firstand second wing members having inboard ends attached to the sides ofsaid tooth respectively, and defining leading edges extending fromlocations respectively rearward and above said cutting edge of saidtooth and immediately adjacent said work surface to locations outward,downward and rearward thereof, the rearward inclination of such leadingedges of said wings defining respective angles less than 30° with avertical plane transverse of the direction of travel of said point, saidwings being constructed and arranged to cooperate with said tooth toimpart a twisting, rolling motion to soil broken and lifted by saidtooth without substantial lateral displacement of said soil.
 2. Thepoint of claim 1 wherein each of said wings is a generally flat memberdefining an upper working surface extending upwardly and rearwardly inslight concave curvature from the leading edge thereof.
 3. The point ofclaim 2 wherein the outer rear portion of each of said wings is turneddownwardly out of planar relation relative to the rest of the uppersurface of said wing.
 4. The point of claim 1 wherein said cutting edgeis substantially straight and transverse of the direction of travel ofsaid tip, and said tooth further defines a generally flat work surfaceinclined rearwardly and upwardly of said leading cutting edge.
 5. Thepoint of claim 1 wherein said cutting edge is curved rearwardly from aleading point and further defining a convex working surface in the formof a knuckle extending upwardly and rearwardly of said cutting edge.